[Xen-devel] [PATCH v4 12/15] xen: arm: handle remaining traps from userspace

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

CP14 dbg and general CP register access are both handled with
unconditional injection of #undef from their respective handlers, so
allow these even from 32-bit userspace on a 64-bit kernel.

SMC32 and HVC32 should only come from a guest in AArch32 mode and
SMC64 and HVC64 should only come from a guest in AArch64 mode. Add
appropriate BUG_ONs to all cases.

After this bad_trap is no longer used.

Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
Reviewed-by: Julien Grall <julien.grall@xxxxxxxxxx>
---
v3: Reintroduce accidentally dropped undef injection from smc64 case.
---
 xen/arch/arm/traps.c |   11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index 9a4deef..53062fe 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -2155,22 +2155,22 @@ asmlinkage void do_trap_hypervisor(struct cpu_user_regs 
*regs)
         do_cp14_32(regs, hsr);
         break;
     case HSR_EC_CP14_DBG:
-        if ( !is_32bit_domain(current->domain) )
-            goto bad_trap;
+        BUG_ON(!psr_mode_is_32bit(regs->cpsr));
         perfc_incr(trap_cp14_dbg);
         do_cp14_dbg(regs, hsr);
         break;
     case HSR_EC_CP:
-        if ( !is_32bit_domain(current->domain) )
-            goto bad_trap;
+        BUG_ON(!psr_mode_is_32bit(regs->cpsr));
         perfc_incr(trap_cp);
         do_cp(regs, hsr);
         break;
     case HSR_EC_SMC32:
+        BUG_ON(!psr_mode_is_32bit(regs->cpsr));
         perfc_incr(trap_smc32);
         inject_undef32_exception(regs);
         break;
     case HSR_EC_HVC32:
+        BUG_ON(!psr_mode_is_32bit(regs->cpsr));
         perfc_incr(trap_hvc32);
 #ifndef NDEBUG
         if ( (hsr.iss & 0xff00) == 0xff00 )
@@ -2182,6 +2182,7 @@ asmlinkage void do_trap_hypervisor(struct cpu_user_regs 
*regs)
         break;
 #ifdef CONFIG_ARM_64
     case HSR_EC_HVC64:
+        BUG_ON(psr_mode_is_32bit(regs->cpsr));
         perfc_incr(trap_hvc64);
 #ifndef NDEBUG
         if ( (hsr.iss & 0xff00) == 0xff00 )
@@ -2192,6 +2193,7 @@ asmlinkage void do_trap_hypervisor(struct cpu_user_regs 
*regs)
         do_trap_hypercall(regs, &regs->x16, hsr.iss);
         break;
     case HSR_EC_SMC64:
+        BUG_ON(psr_mode_is_32bit(regs->cpsr));
         perfc_incr(trap_smc64);
         inject_undef64_exception(regs, hsr.len);
         break;
@@ -2218,7 +2220,6 @@ asmlinkage void do_trap_hypervisor(struct cpu_user_regs 
*regs)
 #endif
 
     default:
- bad_trap:
         printk("Hypervisor Trap. HSR=0x%x EC=0x%x IL=%x 
Syndrome=0x%"PRIx32"\n",
                hsr.bits, hsr.ec, hsr.len, hsr.iss);
         do_unexpected_trap("Hypervisor", regs);
-- 
1.7.10.4


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